Israel had been bracing itself for suicide bombings since its army attempted to kill Sheikh Ahmed Yassin, spiritual leader of the Palestinian militant organisation Hamas.

Hamas had promised to "open the gates of hell", and the country had been put under a high state of alert on Tuesday amid warnings of fresh militant attacks.

Warnings appear to have been focused on northern Israel or Jerusalem after a suspected cell reportedly slipped out of the West Bank town of Nablus.

In the event, bombers did strike in Jerusalem, outside a cafe in a Jewish neighbourhood, but also at a bus stop outside Tzrifin military base near Tel Aviv.

The attacks came as Palestinians were waiting to see what - if anything - their new prime ministerial appointee, Ahmed Qurei, could do to bring progress on the stalled peace plan known as the roadmap.

Indeed, the attempt on Sheikh Yassin - at the house of a Hamas colleague in Gaza on Saturday - coincided with the first moves to have Mr Qurei installed to replace the outgoing PM Mahmoud Abbas, better known as Abu Mazen.

Israeli tried to kill Sheikh Yassin on Saturday

The attempt on the sheikh's life was taken by the Arab side as another sign that Israel had no interest in the roadmap, which is meant to lead to an independent Palestinian state by 2005.

Israel, for its part, has insisted the Palestinian leadership has not fulfilled its roadmap obligation to dismantle "terrorist infrastructure and capabilities" and therefore had to take its own military action.

Textbook operation

By targeting Sheikh Yassin, and before that the successful strike against Hamas political leader Ismail Abu Shanab and the near-miss against Abdel Aziz al-Rantissi, Israel has been pursuing a potentially dangerous escalation in the conflict.

Hamas' verbal response has been to threaten attacks against Israeli political leaders - an ominous echo of events leading up to the killing of an Israeli cabinet minister in October 2001 in revenge for the death of a Palestinian militant leader two months earlier.

However, Tuesday's attack near Tel Aviv - if it is the work of Hamas - is an operation straight out of the Palestinian militant handbook.

Palestinian areas are under huge military pressure

Israeli soldiers travelling to or from military bases have been targets in the past and roadside suicide bombings have the potential to yield high casualties.

One question is whether Hamas will continue to have the capability to launch such attacks - not to mention attacks of the threatened "hellish" scale - if Israel keeps Palestinian areas under the kind of military pressure it has them under now.

It may have failed in the case of Sheikh Yassin but it has succeeded in killing 12 other senior Hamas militants - as well as bystanders - in Gaza in the past three weeks.

But Hamas has deep roots, and it claims - with some credibility - to have hundreds of willing martyrs prepared to strap explosives to their bodies.

The second question is whether Mr Qurei will be any more successful in reining in militant groups than his predecessor, who managed a short hudna (or ceasefire), but that collapsed in flames three weeks ago.

In the wake of Tuesday evening's attacks, the task facing Mr Qurei looks even harder than before.